IRF4 and plasma cell myeloma: These cells included a cluster containing clonal human plasma cells denoted by mRNAs for the IGHG1 and IGL2 genes, the myeloma and plasma cell transcription factors BLIMP1 (22) and IRF4 (23), and the myeloma-associated proteins CD38 (24), CD200 (25), fibroblast growth factor receptor 3 (FGFR3), and nuclear receptor binding SET domain protein 2 (NSD2) (26), the latter 2 resulting from the t(4;14) translocation present in this patient’s myeloma.